udp: secondary hash on (local port, local address)
Extends udp_table to contain a secondary hash table.
socket anchor for this second hash is free, because UDP
doesnt use skc_bind_node : We define an union to hold
both skc_bind_node & a new hlist_nulls_node udp_portaddr_node
udp_lib_get_port() inserts sockets into second hash chain
(additional cost of one atomic op)
udp_lib_unhash() deletes socket from second hash chain
(additional cost of one atomic op)
Note : No spinlock lockdep annotation is needed, because
lock for the secondary hash chain is always get after
lock for primary hash chain.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/udp.h b/include/net/udp.h
index 9167281..af41850 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -63,10 +63,19 @@
spinlock_t lock;
} __attribute__((aligned(2 * sizeof(long))));
+/**
+ * struct udp_table - UDP table
+ *
+ * @hash: hash table, sockets are hashed on (local port)
+ * @hash2: hash table, sockets are hashed on (local port, local address)
+ * @mask: number of slots in hash tables, minus 1
+ * @log: log2(number of slots in hash table)
+ */
struct udp_table {
struct udp_hslot *hash;
- unsigned int mask;
- unsigned int log;
+ struct udp_hslot *hash2;
+ unsigned int mask;
+ unsigned int log;
};
extern struct udp_table udp_table;
extern void udp_table_init(struct udp_table *, const char *);
@@ -75,6 +84,15 @@
{
return &table->hash[udp_hashfn(net, num, table->mask)];
}
+/*
+ * For secondary hash, net_hash_mix() is performed before calling
+ * udp_hashslot2(), this explains difference with udp_hashslot()
+ */
+static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
+ unsigned int hash)
+{
+ return &table->hash2[hash & table->mask];
+}
/* Note: this must match 'valbool' in sock_setsockopt */
#define UDP_CSUM_NOXMIT 1